The primary purpose of this training program is the development of scientific leaders for careers in AIDS research. The current expanding epidemic of HIV infection demands commitment of investigators to the training of a new generation of leaders in research. It is anticipated that graduates of this postdoctoral program will follow careers in laboratory research related to AIDS. This program will provide in depth laboratory experience in a specific research area of virology, immunology, molecular biology, oncology, molecular genetics, or molecular therapeutics to selected candidates. Trainees will be MDs after completion of their clinical residencies and specialty training or PhDs and ScDs from an appropriate basic science program. Criteria for selection will include prior training record, aptitude for research, and commitment to research careers. All applicants will be selected by a Program Steering Committee, and five will be selected annually. Particular emphasis will be given to the recruitment of minorities and others underrepresented in AIDS research, e.g., women. The basic elements of the program are: 1) in depth research training through laboratory investigation of a specific problem in a particular area related to AIDS under a senior investigator;2) a didactic program consisting of appropriately chosen specific courses that will advance the trainee's knowledge;3) frequent exposure to seminars, workshops, and colloquia related to AIDS;and 4) regular review of progress by individual Progress Evaluation Committees and the Program Steering Committee. The primary training facilities consist of well-equipped research laboratories at Harvard Medical School, Harvard School of Public Health, Massachusetts General Hospital, Beth Israel Deaconess Medical Center, Brigham and Women's Hospital, Children's Hospital Boston, Dana-Farber Cancer Institute, and the New England Primate Research Center. Senior faculty at each of these institutions is on the faculty of this grant, and they represent a variety of disciplines. The faculty collaborates with one another on AIDS research and will collaborate in directing this training program.